Fluid transfer pump

ABSTRACT

A fluid transfer pump comprises a cylinder having a suction opening and a discharge opening, a plunger provided within the cylinder movable to and fro in a direction of an axis line of the cylinder, and a membrane-like sealing member for sealing a gap between the cylinder and the plunger, wherein the plunger is driven to and fro for carrying out suction operation and discharge operation alternately, so that fluid is sucked through the suction opening, then the sucked fluid is discharged through the discharge opening, wherein the suction opening is provided on a side portion of the cylinder so that a fluid transfer pump is provided which has an extremely small accumulation rate of fluid, and has good fluid displacement characteristic.

TECHNICAL FIELD

The present invention relates to a fluid transfer pump comprises a cylinder having a suction opening and a discharge opening, a plunger provided within the cylinder movable to and fro in a direction of an axis line of the cylinder, and a membrane-like sealing member for sealing a gap between the cylinder and the plunger, wherein the plunger is driven to and fro for carrying out suction operation and discharge operation alternately, so that fluid is sucked through the suction opening, then the sucked fluid is discharged through the discharge opening. More particularly, the present invention relates to a pump suitable for transferring fluid containing precipitation material, for example resist fluid used for manufacturing liquid crystal substrate, and the like.

BACKGROUND ART

In the past, a fluid transfer pump is employed as means for supplying resist fluid used for manufacturing a liquid crystal substrate to a liquid crystal substrate manufacturing apparatus, the fluid transfer pump comprising a cylinder having a suction opening and a discharge opening, a plunger provided within the cylinder movable to and fro in a direction of an axis line of the cylinder, and a sealing member for sealing a gap between the cylinder and the plunger. The fluid transfer pump has employed an O-ring for the sealing member. The O-ring has outstanding disadvantages such as generation of particles and fluid leakage due to ablation of the O-ring, or a short lifetime. Therefore, the inventors has manufactured a fluid transfer pump employing a membrane-like sealing member instead the O-ring, the membrane-like sealing member being recited in the product catalogue CAT. NO. BFS1-061 of Fujikura Rubber Industrial Co., Ltd. (hereinafter, referred to as a non-patent document 1).

FIGS. 7 are partially cross-sectional front view illustrating a conventional fluid transfer pump 10 employing a membrane-like sealing member recited in the non-patent document 1, wherein FIG. 7(A) illustrates a condition where a plunger 5 is at the bottom dead point, while FIG. 7(B) illustrates a condition where a plunger 5 is at the upper dead point.

As is illustrated in FIGS. 7, a conventional fluid transfer pump 10 comprises a cylinder 20, a plunger 5 and a membrane-like sealing member 6. At the top of the cylinder 20, a suction opening 320 and a discharge opening 330 are formed, the suction opening 320 and discharge opening 330 are in parallel with an axial line J1 of the cylinder 20, respectively. The fluid transfer pump 10 is used in a standing condition. The plunger 5 is driven to and fro so as to perform suction operation and discharge operation one after the other, so that resist fluid is sucked into the cylinder 20 through the suction opening 320, and the sucked resist fluid is discharged from the cylinder 20 through the discharge opening 330.

The membrane-like sealing member 6 consists of a cap-like member made of flexible material (refer to FIG. 2), the upper section of the plunger 5 is covered by the body section 63 of the cap-like member under a condition that the open edge section 62 of the cap-like member is secured to the inner face of the cylinder 20. A U-shaped fold back section 61 having a U-shape in cross-section is formed by folding back the cap-like member downward within a gap G between the cylinder 20 and the plunger 5, and the gap G is sealed by the U-shaped fold back section 61. The U-shaped fold back section 61 moves within the gap G together with the to and fro driving of the plunger 5 in a direction which is the same with the driving direction. During the movement, the U-shaped fold back section 61 moves within the gap G in a trundling manner, so that ablation and loss are small and fluid and gas are not leaked at all.

DISCLOSURE OF THE INVENTION

The U-shaped fold back section 61 is extremely narrow so that resist fluid is likely accumulated within the U-shaped fold back section 61. The accumulated resist fluid is gelated or accumulated over time. Therefore, the gelation or accumulation becomes a cause for containing impurity within resist fluid for supplying to a liquid crystal substrate manufacturing apparatus. A liquid crystal substrate manufacturing apparatus is always required to be supplied resist fluid with high purity. Therefore, a fluid transfer pump with good fluid displacement characteristic, that is a fluid transfer pump with very small accumulation rate of fluid, is required.

The present invention was made to solve such problems. The present invention provides a fluid transfer pump having an extremely small accumulation rate of fluid, and having good fluid displacement characteristic.

To solve the above problems, the invention of the first embodiment comprises a cylinder having a suction opening and a discharge opening, a plunger provided within the cylinder movable to and fro in a direction of an axis line of the cylinder, and a membrane-like sealing member for sealing a gap between the cylinder and the plunger, wherein the plunger is driven to and fro for carrying out suction operation and discharge operation alternately, so that fluid is sucked through the suction opening, then the sucked fluid is discharged through the discharge opening, and wherein the suction opening is provided on a side portion of the cylinder.

In the invention of the second embodiment, the suction opening is provided within an extent which allows forming of the gap when the plunger reaches an upper dead point.

In the invention of the third embodiment, the suction opening is provided so that an axis line of the suction opening is inclined at an angle which is equal to or less than 90 degrees, with respect to the axis line of the cylinder.

In the invention of the fourth embodiment, the suction opening is provided so that an axis line of the suction opening is inclined at an angle which is less than 90 degrees, with respect to a line which is orthogonal to the axis line of the cylinder.

In the invention of the fifth embodiment, the membrane-like sealing member consists of a cap-like member made of flexible material, and a body section of the cap-like member covers the plunger under a condition that an opening edge section of the cap-like member is secured on an inner face of the cylinder, and the gap is sealed by a U-shaped turn back which is formed by turning back downwardly within the gap between the cylinder and the plunger.

In the invention of the sixth embodiment, the cylinder is disposed so that the axis line is vertical.

When the present invention is employed, resist fluid is sucked and blown through the suction opening when the plunger is driven downward. Because the suction opening is provided at the side section of the cylinder, the blowing flow forms circling flow along the inner face of the cylinder and flows downward simultaneously. And, the flow becomes circulating flow which agitates and washes in the interior of the U-shaped turn back section. This results a fluid transfer pump having no accumulation of resist fluid within the U-shaped turn back section, and having good fluid displacement characteristic.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 are partially cross-sectional front views illustrating a fluid transfer pump of an embodiment according to the present invention;

FIG. 2 is a perspective view illustrating an exterior appearance of a membrane-like sealing member;

FIGS. 3 are schematic views illustrating a fluid transfer pump of an embodiment according to the present invention;

FIGS. 4 are partially cross-sectional plan views illustrating a fluid transfer pump of another embodiment according to the present invention;

FIGS. 5 are partially cross-sectional views illustrating a fluid transfer pump of a further embodiment according to the present invention;

FIGS. 6 are schematic views illustrating a fluid transfer pump of a further embodiment according to the present invention; and

FIGS. 7 are partially cross-sectional front views illustrating a conventional fluid transfer pump.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, referring to the attached drawings, we explain the best mode for carrying out the present invention.

FIGS. 1 are partially cross-sectional front views illustrating a fluid transfer pump 1 according to the present invention, wherein FIG. 1(A) illustrates a condition where a plunger 5 is at a bottom dead point, while FIG. 1(B) illustrates a condition where a plunger 5 is at an upper dead point. FIG. 2 is a perspective view illustrating an exterior appearance of a membrane-like sealing member 6. FIGS. 3 are schematic views illustrating a fluid transfer pump according to the present invention.

Hereinafter, description is made by taking a case as an example where fluid is resist fluid. It is of course possible that fluid other than resist fluid is employed.

As is illustrated in FIGS. 1, a fluid transfer pump 1 according to the present invention comprises a cylinder 2, a plunger 5, and a membrane-like sealing member 6.

The cylinder 2 comprises an upper cover member 3 having a schematic saucer-shape having an ear section 31, and a lower cover member 4 having a schematic saucer-shape having an ear section 41 similarly. The upper cover member 3 and the lower cover member 4 become unified so as to form a cylinder main body by fastening the ear section 31 and the ear section 41 using bolts 42 under a condition that an opening edge section 62 of the membrane-like sealing member 6 is clamped between respective ear section 31 and ear section 41.

The upper cover member 3 is thirled to form an suction opening 32 and a discharge opening 33. The suction opening 32 is thirled in the side section of the upper cover member 3. Also, the suction opening 32 is thirled within an extent R where a gap G is formed when the plunger 5 reaches the upper dead point. Further, the suction opening 32 is thirled so that its axis line J0 is inclined by an angle θ with respect to an axis line J1 of the cylinder 2. The angle θ is equal to or less than 90 degrees. The minimum value of the angle θ is an angle which at least a part of an ellipse arc of the suction opening 32 is hit with a flange section of the membrane-like sealing member 6 {refer to FIGS. 3(A) and 3(B)}. And, the suction opening 32 is thirled so that its axis line J0 is inclined by an angleφ with respect to a straight line J2 orthogonal to an axis line J1 of the cylinder 2, as is illustrated in FIG. 3(C). Most preferable extent of the angleφ is an extent where a hole of which center is an axis line J0 has tangent relationship with an inner periphery of the cylinder 2 (an extent where a straight line belonging to the hole and parallel to the axis line J0 becomes a tangent line with respect to the inner periphery of the cylinder 2){refer to FIG. 3(D}}. The discharge opening 33 is thirled at the top section of the upper cover member 3 in a direction parallel to the axis line J1 of the cylinder 2. It is possible that a direction changeover valve or the like (not shown) is provided and the suction opening 32 doubles with a discharge opening.

The lower cover member 4 is thirled to form a vacuuming opening 43 and a rod hole 44. The vacuuming opening 43 is jointed to a vacuum pump 73 at a lower position of the lower cover member 4. By vacuuming so as to decrease pressure within a lower chamber of the cylinder 2 by the vacuum pump 73, adhesiveness of the membrane-like sealing member 6 and the exterior periphery face of a head 51 and the inner periphery face of the cylinder 2 is improved, and gas is effectively prevented from coming to be mixed in an upper chamber of the cylinder 2. The rod hole 44 is a through hole for passing through a rod 53 in a slidable manner, and is thirled at the bottom section of the lower cover member 4.

The plunger 5 comprises the head 51, a seat plate 52, and the rod 53. The rod covered by the membrane-like sealing member 6 is connected to the rod 53 through the seat plate 52 by a bolt 54. The rod 53 passing through the rod hole 44 is connected its other end to a driving device (not shown). Thereby, the plunger 5 can move to and fro within the cylinder 2.

The membrane-like sealing member 6 consists of a cap-like member made of flexible material. The flexible material may be, for example material made by covering forcible polyester cloth with rubber. The membrane-like sealing member 6 seals the gap G, the sealing operation is as follows. That is, the upper section of the plunger 5 is covered by the body section 63 of the cap-like member under a condition that the opening edge section 62 of the membrane-like sealing member 6 is secured to the inner periphery face of the cylinder 2. Then, a U-shaped turn back section 61 having a U-shaped cross-section is formed by turning back the cap-like member downwardly within the gap G between the cylinder 2 and the plunger 5. The U-shaped turn back section 61 seals the gap G.

The fluid transfer pump 1 having the above arrangement, is used in a standing condition. The plunger 5 is driven to and fro for carrying out suction operation and discharge operation alternately, so that fluid is sucked through the suction opening 32 within the cylinder 2, then the sucked fluid is discharged through the discharge opening 33.

When the plunger 5 is driven downwardly, supplied resist fluid is blown from the suction opening 32 through a check valve 71. The blowing flow forms circling flow along the inner face of the cylinder 2 and flows downward simultaneously. And, the flow becomes circulating flow which agitates and washes in the interior of the U-shaped turn back section 61. This results no accumulation of resist fluid within the U-shaped turn back section 61, and good fluid displacement characteristic.

Resist fluid flowed within the cylinder 2 is pressurized and discharged through the discharge opening 33 by driving the plunger 5 upwardly, and is supplied to a liquid crystal substrate manufacturing apparatus (not shown) through a check valve 72.

The U-shaped turn back section 61 moves within the gap G in a direction together with the to and fro driving of the plunger 5, the direction being the same with the driving direction. During the movement, the U-shaped turn back section 61 moves within the gap G in a trundling manner, so that ablation and loss are small and fluid and gas are not leaked at all.

Next, a fluid transfer pump 1A of another embodiment according to the present invention is described. FIG. 4 is a partially cross-sectional plan view illustrating a fluid transfer pump 1A of another embodiment according to the present invention.

As is illustrated in FIG. 4, the fluid transfer pump 1A comprises an upper cover member 3A instead the upper cover member 3 for the fluid transfer pump 1. Arrangements other than the upper cover member 3A are the same to those of the fluid transfer pump 1, therefore description of the arrangements is omitted.

The upper cover member 3A comprises a suction opening 32A in addition to the suction opening 32, the suction opening 32A having a shape same with the suction opening 32 of the fluid transfer pump 32, the suction opening 32A being provided at a symmetry site with the suction opening 32 with respect to the center of the upper cover member. By employing the arrangement, resist fluid blowing from the suction openings 32 and 32A during the sucking operation, circulate in a same direction, respectively, as is illustrated by arrows W2 in FIG. 4, therefore the speed of the circulating flow is increased greater than that of the case in which only one suction opening is provided so that the above operation and effect are further improved.

Further, a fluid transfer pump 1B of a further embodiment according to the present invention is described. FIGS. 5 are partially cross-sectional views illustrating a fluid transfer pump 1B of a further embodiment according to the present invention, wherein FIG. 5(A) illustrates a partially cross-sectional front view, while FIG. 5(B) illustrates a partially cross-sectional plan view.

As is illustrated in FIGS. 5, the fluid transfer pump 1B comprises an upper cover member 3B instead the upper cover member 3 for the fluid transfer pump 1. Arrangements other than the upper cover member 3B are the same to those of the fluid transfer pump 1, therefore description of the arrangements is omitted.

The upper cover member 3B comprises a suction opening 32B at a side section of the upper cover member 3B. An axis line J0 of the suction opening 32B is at 90 degrees with respect to the axis line J1 of the cylinder. Also, the axis line J0 is at 0 degrees with respect to a straight line J2 orthogonal to the axis line J1 of the cylinder. By employing the arrangement, resist fluid blowing from the suction opening 32B during the sucking operation, is divided into both side flows and each flow circulates along the inner face of the cylinder and flows downward simultaneously, as is illustrated in FIG. 5(B). The circulating flows formed by dividing the fluid flow into both side flows collided to one another in a side section opposite to the suction opening 32B, and flow together upwardly {refer to FIGS. 5(C) and 5(D)}. As a result, the interior of the U-shaped turn back section 61 is agitated similarly to the case of the fluid transfer pump 1 so that fluid displacement characteristic is improved.

Specifically, fluid displacement test is carried out under a condition that the plunger 5 is at the upper dead position.

When resist fluid is filled within the cylinder, and cleaning fluid for fluid displacement is supplied from the suction opening 320 in FIGS. 7 with pressure of 0.05 Mpa, resist fluid accumulated within the U-shaped turn back section is not perfectly displaced even when total amount of 10 liters of cleaning fluid for fluid displacement is kept to be supplied for 5 minutes under a condition that the plunger is stopped.

On the contrary, when the embodiment illustrated in FIGS. 5 is employed, and when the similar test operation is carried out, resist fluid accumulated within the U-shaped turn back section is perfectly displaced when total amount of 4 liter of cleaning fluid for fluid displacement is kept to be supplied for 2 minutes.

Displacement is improved by discharge (cleaning) of accumulated material, saving of fluid for displacement, and shortage of required time period, so that productivity rate is greatly improved. When the accumulated material enters a liquid crystal substrate, it becomes defection. The smaller amount of fluid for displacement (cleaning fluid), the better for cost reduction and for environment. Short time period for displacement shortens stop time of liquid crystal substrate manufacturing apparatus due to maintenance such as periodic cleaning, so that productivity rate is improved.

In each of the above embodiments, the cylinder 2 is disposed so that the axis line J1 is vertical, but it is possible that the cylinder 2 may be disposed so that the axis line J1 is horizontal.

FIGS. 6 are schematic views illustrating an embodiment in which a cylinder 2C is disposed so that an axis line J1 of the cylinder 2C is horizontal.

As is illustrated in FIGS. 6(A) and 6(B), a discharge opening 33C should be disposed at the uppermost section of the cylinder 2C. A suction opening 32C may be thirled so that an axis line J0 of the suction opening is in parallel with an axis line J3 of the discharge opening 33C, as is illustrated in FIG. 6(A). Also, a suction opening 32C may be thirled so that an axis line J0 of the suction opening 32C is inclined by an angle θ with respect to an axis line J1 of a cylinder 2C, as is illustrated in FIG. 6(B). Further, a suction opening 32C may be thirled so that an axis line J0 of the suction opening 32C is inclined by an angle φ with respect to a straight line J2 orthogonal to an axis line J1 of a cylinder 2C. By the arrangement, circulating flow in one direction is realized. In this case, an angle extent α is preferably to be greater than 180 degrees, the angle extent being an extent in which circulating flow is formed. It is also possible that an inclination angle φ may be 0 degrees. In this case, an suction opening 32C is preferable to be thirled on opposite side with respect to a discharge opening 33C.

In the foregoing, description was made for embodiments of the invention. The embodiments disclosed above are merely exemplification, and the scope of the invention is not limited to those embodiments. The scope of the present invention is represented by the representation of claims. And, it is intended that all modification within equivalent meanings and scope of claims. 

1. A fluid transfer pump comprising: A cylinder having a suction opening and a discharge opening; A plunger provided within the cylinder movable to and fro in a direction of an axis line of the cylinder; and A membrane-like sealing member for sealing a gap between the cylinder and the plunger, Wherein the plunger is driven to and fro for carrying out suction operation and discharge operation alternately, so that fluid is sucked through the suction opening, then the sucked fluid is discharged through the discharge opening, Wherein the suction opening is provided on a side portion of the cylinder.
 2. A fluid transfer pump as set forth in claim 1, wherein the suction opening is provided within an extent which allows forming of the gap when the plunger reaches an upper dead point.
 3. A fluid transfer pump as set forth in claim 1, wherein the suction opening is provided so that an axis line of the suction opening is inclined at an angle which is equal to or less than 90 degrees, with respect to the axis line of the cylinder.
 4. A fluid transfer pump as set forth in claim 2, wherein the suction opening is provided so that an axis line of the suction opening is inclined at an angle which is equal to or less than 90 degrees, with respect to the axis line of the cylinder.
 5. A fluid transfer pump as set forth in claim 1, wherein the suction opening is provided so that an axis line of the suction opening is inclined at an angle which is less than 90 degrees, with respect to a line which is orthogonal to the axis line of the cylinder.
 6. A fluid transfer pump as set forth in claim 2, wherein the suction opening is provided so that an axis line of the suction opening is inclined at an angle which is less than 90 degrees, with respect to a line which is orthogonal to the axis line of the cylinder.
 7. A fluid transfer pump as set forth in claim 3, wherein the suction opening is provided so that an axis line of the suction opening is inclined at an angle which is less than 90 degrees, with respect to a line which is orthogonal to the axis line of the cylinder.
 8. A fluid transfer pump as set forth in claim 1, wherein the membrane-like sealing member consists of a cap-like member made of flexible material, wherein a body section of the cap-like member covers the plunger under a condition that an opening edge section of the cap-like member is secured on an inner face of the cylinder, and wherein the gap is sealed by a U-shaped turn back which is formed by turning back downwardly within the gap between the cylinder and the plunger.
 9. A fluid transfer pump as set forth in claim 2, wherein the membrane-like sealing member consists of a cap-like member made of flexible material, wherein a body section of the cap-like member covers the plunger under a condition that an opening edge section of the cap-like member is secured on an inner face of the cylinder, and wherein the gap is sealed by a U-shaped turn back which is formed by turning back downwardly within the gap between the cylinder and the plunger.
 10. A fluid transfer pump as set forth in claim 3, wherein the membrane-like sealing member consists of a cap-like member made of flexible material, wherein a body section of the cap-like member covers the plunger under a condition that an opening edge section of the cap-like member is secured on an inner face of the cylinder, and wherein the gap is sealed by a U-shaped turn back which is formed by turning back downwardly within the gap between the cylinder and the plunger.
 11. A fluid transfer pump as set forth in claim 4, wherein the membrane-like sealing member consists of a cap-like member made of flexible material, wherein a body section of the cap-like member covers the plunger under a condition that an opening edge section of the cap-like member is secured on an inner face of the cylinder, and wherein the gap is sealed by a U-shaped turn back which is formed by turning back downwardly within the gap between the cylinder and the plunger.
 12. A fluid transfer pump as set forth in claim 1, wherein the cylinder is disposed so that the axis line is vertical.
 13. A fluid transfer pump as set forth in claim 2, wherein the cylinder is disposed so that the axis line is vertical.
 14. A fluid transfer pump as set forth in claim 3, wherein the cylinder is disposed so that the axis line is vertical.
 15. A fluid transfer pump as set forth in claim 4, wherein the cylinder is disposed so that the axis line is vertical.
 16. A fluid transfer pump as set forth in claim 5, wherein the cylinder is disposed so that the axis line is vertical. 